Rarely does the need to know how to prune rhododendrons ever come up if the correct variety has been chosen. About the only time they really should be pruned at all is to take out any dead wood or branches that appear to harbor disease or insects. It is fortunate for rhodo lovers that this plant has been hybridized into so many different cultivars that there is a variety for nearly any planting situation.
For instance, for small areas, Ginny Gee, Ramapo, and Impeditum, reach a mere one-to-two feet high and are only three feet wide. Howtei, Snow Lady, and Bow Bells, grow only three feet in height and four feet wide.
Mid-sized rhodos include Daphnoides, Ken Janeck, and Nova Zembla, which all grow between four and six feet tall with those same width dimensions. Tall, tree-sized rhododendrons include the varieties of King George, Blaney Blue, and Rex.
But if you have found yourself with one or more rhododendron bushes that suffer from crowding, are growing over a sidewalk, encroaching upon other plants, or are in other some such circumstances that call for a little cutting back, read on for a few good tips on how to prune rhododendrons.
Pruning With Blooms in Mind
If a great showing of blossoms is important to you, it is significant to know how to prune rhododendrons to avoid affecting the formation of flower buds the following year. Rhodos set their buds on old wood, so make cuts only when the plant is blooming or immediately afterward so that you can tell which branches are old and which are new.
When you do make your cuts, do so just above the truss or flower cluster. This new growth will not be missed by the plant and by eliminating it, it will cause the plant to become bushier. Energy that was once being directed into making seeds will now go into making more foliage.
The smaller, more compact varieties of rhododendrons do not require any sort of pruning at all. Deadheading them can help produce the maximum amount of blooms on these dwarf varieties of rhodos, but these cultivars have been bred so that they produce such an abundance of blooms anyway, if you neglect taking off the old flowering clusters, you may not notice much of a bloom loss at all. Of course, how to prune rhododendrons of these varieties is a much easier task and one of the reasons these types of rhodos have become so popular over the years.
Other people who know how to prune rhododendrons intentionally choose to cut them severely, sometimes all the way back to the ground. The argument here is that even thought it will take the plant up to two years to get back to the stage where its blooms are profuse, it is worth it to give the plant time to recuperate and regenerate, especially if it is an old favorite and replacing the rhodo entirely is not a preferred option. Late fall or early spring pruning is acceptable for those not concerned with bloom set.
These members of the Ericaceae family are such a wonderful addition to almost any landscape and knowing how to prune rhododendrons properly can help even whether you covet their famous blooms or not. So take your time, make your cuts thoughtfully, and enjoy your favorite rhodos to their fullest!